beneath the table to the abstract. Use the Word Count cmd under Utilites menu for counting Significance Bartonellosis, caused by infection with the bacteria Bartonella henselae or B. quintana, is emerging as an important opportunistic infection in patients with AIDS. Bartonella henselae is the etiologic agent of cat-scratch disease, while B. quintana is the agent of "trench fever", both self-limiting infections in immunocompetent hosts. Bartonella infection in AIDS patients, or other immune compromised hosts, however, has been associated with a severe life threatening proliferation of vascular tissue affecting multiple organ systems; a condition referred to as bacillary angiomatosis (BA) or bacillary peliosis. The pathogenetic mechanisms leading to the development of these lesions are unknown. Objectives To utilizing the SIV/macaque model system to determine the pathogenesis of Bartonella infection in SIV-infected, immunocompromised macaques, and to evaluate the utility of the SIV/macaque system as a potential model for BA. SIV-infected animals, at various stages of immunodeficiency, will be inoculated with Bartonella spp. and monitored for onset, duration, immune response, and clinical outcome of bacteremia. Results Bartonella bacteremias have been established in SIV-infected macaques having specific immunologic parameters. Monitoring of these animals for characterization of clinical course and long-term sequelae is on-going. Future Directions Additional Bartonella inoculations will be performed in SIV-infected and SIV-uninfected macaques to expand studies of pathogenesis and further model development. KEY WORDS Bartonella, bacillary angiomatosis, SIV, AIDS, rhesus macaque FUNDING NIH RR00169 Pilot Study - Study Complete - Funded by NIH 12/1/98 A143703